1. Field of the Invention
The present invention relates to a touch panel interface system, a touch controlled device, and a method, and more particularly, to a touch panel interface system, a touch device, and a method, for applying serial peripheral interface on large-scale touch panels with the aid of a complex programmable logic device.
2. Description of the Prior Art
A serial peripheral interface refers to a four-wired synchronous data protocol, and is conventionally implemented on a platform of a portable electronic device. Moreover, when the serial peripheral interface is applied on a touch panel, said serial peripheral interface is conventionally applied on a small-scale touch device, which may also be denoted as a touch-controlled device, such as a touch panel having four inches in size.
Please refer to FIG. 1, which illustrates applying a serial peripheral interface bus on a small-scale touch device 100 in the prior art. As shown in FIG. 1, the touch device 100 includes a touch panel interface system 150 and a touch panel 140. The touch panel interface system 150 includes a microprocessor 110, a sensor 120, and a serial peripheral interface bus 130. The sensor 120 is used for sensing triggered signals on the touch panel 140, and for transmitting the sensed signals to the microprocessor 110 through the serial peripheral interface bus 130 so that the microprocessor 110 may determine a corresponding triggered location of a user on the touch panel 140. The microprocessor 110 also generates a command to the sensor 120 for ordering the sensor 120 to sensing signals triggered on the touch panel 140, where the microprocessor 110 also transmits commands generated by itself to the sensor 120 through the serial peripheral interface bus 130.
Please refer to FIG. 2, which is a schematic diagram of applying the serial peripheral interface bus on a large-scale touch device 200 in the prior art. As shown in FIG. 2, the touch device 200 includes a touch panel interface system 250 and a touch panel 240. The touch panel interface system 250 includes a microprocessor 210, a plurality of sensors 222, 224, 226, and a plurality of serial peripheral interface buses 232, 234, 236, each of which corresponds to a specific one among the plurality of sensors 222, 224, 226 in a one-by-one correspondence. Assume that the touch panel 240 is larger than the touch panel 140 shown in FIG. 1 by some multiple size of the touch panel 140 in area, and therefore, each of the serial peripheral interface buses 232, 234, and 236 may merely sense part of triggered signals on the touch panel 240 through a corresponding sensor, i.e., one of the sensors 222, 224, and 226, where each of the sensors 222, 224, and 226 is responsible for sensing triggering conditions on different and exclusive regions on the touch panel 240. Since a conventional microprocessor 210 merely support a single serial peripheral interface bus implemented by hardware, other un-supported serial peripheral interface buses may merely be simulated by software. In other words, the serial peripheral interface bus 232 may be assumed to be the hardware serial peripheral interface bus directly supported by the microprocessor 210, whereas the serial peripheral interface buses 234 and 236 are implemented and simulated by software. However, since a clock of a software-simulated serial peripheral interface, which is denoted as software-simulated clock hereafter, is far slower than a hardware clock of the hardware-implemented serial peripheral interface, taking the touch device 200 shown in FIG. 2 as an example, data transmission between the microprocessor 210 and the software-simulated serial peripheral interface buses 234 and 236 cannot keep up with data transmission between the microprocessor 210 and the hardware-implemented serial peripheral interface bus 232 in speed, and the microprocessor 210 requires more execution time in the software-simulated serial peripheral interface buses 234 and 236 as a result so that the microprocessor 210 is able to process sensing signals from the sensors 222, 224, and 226 synchronously.
Please refer to FIG. 3, which schematically illustrates clocks of the microprocessor 210 shown in FIG. 2. According to the above assumption, while the serial peripheral interface bus 232 is implemented by hardware and uses a hardware clock, whereas both the serial peripheral interface buses 234 and 236 are simulated by software and uses a software-simulated clock, the hardware clock is much faster than the software-simulated clock so that the microprocessor 210 has to take a larger ratio of execution time on both the software-simulated serial peripheral interface buses 234 and 236.
In summary, since the software-simulated clock used by the microprocessor cannot match the hardware clock of the hardware-implemented serial peripheral interface bus in speed so that the hardware clock has to be reduced for cooperating with the slower software-simulated clock, and the speed of the microprocessor in processing the sensing signals may be reduced as a result. Besides, since the microprocessor requires additional execution time in processing coordination between the sensing signals returned by the sensors, a processing speed of the microprocessor is also reduced because of an additional and significantly-increased burden in processing the sensing signals.